Are Deep Squats Bad for Your Knees?

“Ha! Look at these goobers thinking their 300-pound ass-to-grass squats are better than my 400-pound parallel squats. I’m lifting more weight and being smarter about my injury risk. Don’t they know deep squats will blow their knees out?”

Nnnnnah. The fact that it’s way harder to squat deep with as much weight as you use to squat to parallel might be an acceptable reason to avoid squatting very deep. It’s an honest reason, at least. But the position that you won’t squat deep because it’s bad for you doesn’t hold much water. Or at least, it needs to come with some serious caveats.

Are Deep Squats Bad for Knees?

“It’s been a fearmongering tactic that came out from these studies in the ‘50s and ‘60s that made everyone scared you’d tear your ACL, but that’s not the case,” says Dr. Aaron Horschig, a sports and orthopedic physical therapist, Olympic weightlifter, and founder of Squat University. “The ligaments are very safe, they’re not placed on that much of a stretch in deep squat — they’re actually loaded much earlier in the squat motion.”

Research agrees that forces inside the ACL and PCL (two major ligaments in the knee) decrease the more the knee is bent. Theoretically, if there were an issue, it’d be with pressure on the meniscus or the patellar, because those two areas have more contact the deeper the squats go. Some folks argue that lots of deep squats lead to early onset of arthritis because, theoretically, they would gradually wear away the smooth underlining of the cartilage or the meniscus.

But a lot of research appears to show little difference between deep and shallow squats as far as impact on the patellofemoral joint.

“When you look at the research, we don’t see those connections,” says Horschig. “No research shows powerlifters and weightlifters have more arthritis in the knees than in the general population, and they’re squatting deep all the time, particularly those doing snatches and clean & jerks.”

A standard response to this might be, “So why do my knees hurt during a deep squat, smart guy?”

Well, knee pain has a ton of causes that are beyond the scope of this article. With athletes, common causes can be weak or inactive glutes, ankle instability, poor posture, weak calves, or a history of history of knee valgus, among other potential causes. And sure, it can be caused by forms of arthritis and other chronic problems. But caused by deep squatting? Probably not, but again, there are a couple of asterisks.

Deep Squats Form

“Deep squats are very safe if two things come along with them,” says Horschig. “You have to use good technique to get there and you have to use good programming as far as intensity, volume, and reps.”

That might seem obvious, but we all know a lot of people who lift to failure every time they squat. “It’s better for testosterone, bro!” Well, it’s bad for an awful lot of other things, two of which are your knees. If you train heavy all the time and don’t leave the body time to adapt, the chance of having a problem with deep squatting is high because there’s a lot of compression placed on both parts of the knee joint.

“If you’re bouncing like crazy, or your knees are jamming forward at the start of the squat, of if you’re knee dominant, that’ll result in an increase of forces on the knee joint,” Horschig notes.

Pay a lot of attention to mobility, do a full body dynamic warm up, engage all the right muscles, and now the tough pill to swallow: decrease weight if you can’t squat as much as you’d like. We know, that’s never fun to hear.

Then there’s programming. Squatting heavy all the time is one bad way to go about periodization, but there are a lot of other mistakes you can make: overdeveloping the quads at the expense of the hamstrings or glutes, not using the right weights at the right time, or — and this is an important one — working out based on when your muscles feel fine instead of taking into account that your joints and cartilage also need to recover.

“When you perform any kind of exercise on your body, your bones and cartilage adapts in a similar way to the muscles,” says Horschig. “If you constantly lift heavy or have bad programming, eventually you reach a point where the body is unable to adapt and will start degrading.”

What About Butt Wink?

Ah, butt wink. For a lot of people, a deep squat has a detested consequence: the butt stops sticking out and begins to slowly curl underneath the torso. Butt wink is controversial, but the general idea is that it’s a posterior rotation of the pelvis wherein it pulls under the body. Over many, many squats and many months or years, it may cause issues in the lumbar spine, like a disc bulge.

There are a few things that could help. Limited ankle mobility can result in the hips moving excessively to continue the depth of the squat. Spending a bunch of time working on your ankle mobility (hey, we’ve got an article on that) can make a world of difference among some athletes. Sometimes it can be a form issue as well, as many athletes find butt wink disappears with a wider stance.

“Other than that, it can be genetic, just a result of your natural hip anatomy,” says Horschig. “To that extent, we may not be able to change that and if improving the ankles and the stance don’t help, I may talk to that person about possibly limiting the depth of their squat.”

Wrapping Up

Squatting deep is pretty great, probably works the glutes more, and is more challenging. But you probably can’t lift as much weight, some people get too much butt wink, some people can’t or won’t fix the knee pain it might bring, and it’s not totally totally necessary to be an excellent powerlifter.

It’s worth taking some of the steps outlined above to perfect your form, minimize your injury risk, and work deep squats into your routine when appropriate. But if you don’t want to, that’s cool, too.

Nick is a content producer and journalist with over seven years’ experience reporting on four continents. His first articles about health were on a cholera outbreak in rural Kenya while he was reporting for a French humanitarian organization. His next writing job was covering the nightlife scene in Shanghai. He’s written on a lot of things.

After Shanghai, he went on to produce a radio documentary about bodybuilding in Australia before finishing his Master’s degrees in Journalism and International Relations and heading to New York City. Here, he’s been writing on health full time for more than five years for outlets like BarBend, Men's Health, VICE, and Popular Science.

No fan of writing in the third person, Nick’s passion for health stems from an interest in self improvement: How do we reach our potential?

Questions like these took him through a lot of different areas of health and fitness like gymnastics, vegetarianism, kettlebell training, fasting, CrossFit, Paleo, and so on, until he realized (or decided) that strength training fit best with the ideas of continuous, measurable self improvement.

At BarBend his writing focuses a little more on nutrition and long-form content with a heaping dose of strength training. His underlying belief is in the middle path: you don’t have to count every calorie and complete every workout in order to benefit from a healthy lifestyle and a stronger body. Plus, big traps are cool.

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